1. Field Of The Invention
This invention relates to a motor vehicle headrest structure and, more particularly, to a motor vehicle headrest including an armature assembly comprising a plastic armature to which individual support posts are securely fastened.
2. Background Of The Invention
Headrests of various designs and construction are used in automobiles and other motor vehicles to protect passengers from injury in the event of an accident. Such headrests typically consist of a metal or plastic form, or armature, surrounded by suitable padding and a cover, supported by post means extending upwardly from the motor vehicle seat back. The armature provides a framework to support the padding and cover of the headrest assembly. Such headrests may be adjustable with respect to the seat back.
Previous motor vehicle headrests have utilized armatures made of metal or plastic, typically formed to provide, when covered with padding, a flat or convex finished surface adjacent the passenger's head. Typical post means used in motor vehicle headrests have included one piece inverted U-shaped posts and hollow metal tubes. Means for attaching the armature to the post means have included welding and insert molding of the armature to the post.
When the headrest armature is made from blow molded or injection molded plastic, the post means may be joined integrally to the armature by providing the post means as a mold insert. However, the use of mold inserts presents several potential disadvantages. The insertion of the post members into the mold during manufacture can be complicated and expensive.
In addition, the presence of metal insert elements in the molded part may also cause uneven cooling and dimensional distortion of the plastic armature. For example, U.S. Pat. No. 4,734,244 describes the problem of movement of the metal inserts within the plastic headrest armature during the post-molding cooling process. That patent discloses a mold and method to create internal structures in the headrest core to restrict movement of the metal insert during the cooling process. Such structures may make the molding process more complex and expensive.
Moreover, removal of flash or other excess material from the finished assembly may be more difficult because of the protruding metal insert. Finally, should one or more of the component pieces shift during the molding process, it may be difficult to rework, repair or salvage the assembly or its components.
Accordingly, a need has remained for an improved headrest armature design that may be produced reliably at reduced cost.